LED Chromaticity Control via Driving Schema Adjustment
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Solution Overview
Problem
Manufacturing process variations in solid-state illumination sources, such as LEDs, lead to inconsistencies in the spectral composition of emitted light, making it costly to select LEDs with tightly controlled and matched light outputs, especially in applications where chromaticity is critical.
Innovation Solution
A driving circuit and method that control the driving current of LEDs using a driving schema and control value to alter chromaticity while maintaining brightness, allowing for the adjustment of spectral characteristics of LEDs to match or differ, enabling the use of LEDs with mis-matched spectral characteristics in arrays and providing fine control over light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If LEDs are sorted into bins based on chromaticity to ensure consistent light output, then chromaticity control is improved, but cost increases significantly
Solution Approach 1:
The patent changes the driving parameters (current, pulse width, duty cycle) of LEDs to adjust their chromaticity output. By varying these electrical parameters, LEDs from different bins can be made to emit light with matched chromaticity characteristics, eliminating the need to purchase expensive bin-matched LEDs while maintaining consistent color output across the display array.
2Reliability
If LEDs with tightly controlled and matched light outputs are selected for high quality displays, then chromaticity consistency is improved, but cost increases
Solution Approach 1:
The system measures the actual chromaticity output of each LED and uses this feedback information to determine appropriate driving parameters for that specific LED. This allows the system to compensate for manufacturing variations in each individual LED, achieving consistent chromaticity across all LEDs in the display without requiring expensive pre-sorted bin-matched components.
Solution Approach 2:
Different driving parameters are applied to individual LEDs based on their measured characteristics. By adjusting current levels, pulse widths, and duty cycles, the system compensates for variations in LED chip characteristics, enabling LEDs from different manufacturing bins to produce consistent chromaticity output in the final display.
3Manufacturing precision
If process variations in LED manufacturing are reduced to ensure consistent spectral composition, then chromaticity control is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The system allows LEDs to self-characterize by measuring their individual chromaticity output and automatically determining their optimal driving parameters. This self-service approach compensates for manufacturing variations without requiring complex manufacturing process controls, as each LED adjusts its output based on its own measured characteristics rather than relying on tight manufacturing tolerances.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the generation of light with precise chromaticity control, allowing for the use of less expensive LEDs with shifted spectral characteristics, reducing costs and improving the quality of light output in displays and other applications.
Implementation Method 1
a light-emitting diode. The apparatus includes a control circuit configured to alter the driving schema
Implementation Method 2
light emitting diodes and other solid-state illumination sources
Data Source
AI summary
Chromaticity of light output by a light-emitting diode, such as a light-emitting diode (LED), is adjusted while maintaining a brightness of the illumination source substantially constant by adjusting a drive schema for the illumination source. A driver for LEDs or other light-emitting diodes provides for varying a drive schema to adjust chromaticity of driven LEDs.